Quick stranding machine

ABSTRACT

PCT No. PCT/DE78/00041 Sec. 371 Date Aug. 21, 1979 Sec. 102(e) Date Aug. 20, 1979 PCT Filed Dec. 16, 1978 PCT Pub. No. WO79/00414 PCT Pub. Date July 12, 1979 
     A high-speed stranding machine has a hollow rotor, at least one spool carrier arranged in the rotor independently of the rotation of the rotor, and an unbalanced mass preventing rotation of the spool carrier together with the rotation of the rotor and formed as a counterweight. The spool carrier with a spool carried thereby has a center of gravity substantially coinciding with the axis of rotation of the rotor, and the counterweight is connected with the spool carrier in such a manner that the counterweight can independently rotate about the axis of rotation of the rotor, and can be disconnected from the spool carrier upon exceeding a predetermined torque in a connecting element which connects the counterweight with the spool carrier.

BACKGROUND OF THE INVENTION

This invention relates to a high-speed stranding machine with at leastone spool carrier held in floating bearings, prevented from rotatingtogether with the rotor, inside which it is located, by an unbalancedweight. With these machines, known for example from the German LettersPatent DT-PS No. 23 37 305, the rotor is driven at high speeds. A wireruns off from every spool inside the rotor, the spools being supportedso they can rotate by the spool carrier which itself is not rotatingtogether with the rotor. The wires from all spools of the machine areled out of the rotor to the point of combination and are stranded thereby the rotation of the rotor.

In order to ensure that the spool carrier will not rotate together withthe rotor, it is, with the machines known, designed asymmetrical, sothat its center of gravity will be located below its axis of rotation.Thus, its position during normal operation will be stable and it willjust swing lightly to and fro. In case of the swinging becoming toolarge, a so-called swing safety will cause emergency braking andshutting-down of the machine.

It is also known how to arrange the position of the spool below the axisof rotation of the spool carrier, this in order to prevent the spodcarrier from co-rotating.

Yet, malfunctioning during operations, when the spool carrier may comeinto rotation, cannot be eliminated altogether. An acceleration of thespool carrier may be caused by a defective spool-carrier bearing, by abroken wire or by a wire that has become wedged between the spoolcarrier and the rotor. The speed of rotation which the spool carrierwill reach, depends upon the ratio of the momentum of inertia of therotor to that of the spool carrier with spool, upon the braking time andupon the torque generated between rotor and spool carrier when, forinstance, seizure occurs in a bearing. If such a torque is very high(magnitude of 10,000 N.m), acceleration will be so high that the spoolcarrier will approximately reach the full rotor speed, although theswing safety will respond correctly. Very high stresses by thecentrifugal forces will result as a consequence and will be transmitted,via the spool carrier bearings onto the rotor, the rotor supports andthe foundation which may be damaged or destroyed within fractions of asecond. A rotor supported by trunnion rollers would be lifted from theserollers. The centrifugal force acting upon the locking parts of thespool carriers may be of such magnitude that the lock will open; thespool would then fly out. The stress exerted upon the spool-carrier wallby the centrifugal force resulting from its own weight and from thespool which is unevenly wound and displaced from the center, may be solarge that with customary spool holders, the bending stress will behigher than the breaking limit.

SUMMARY OF THE INVENTION

It is the task of the invention, to construct a high-speed strandingmachine in such a manner that on one hand the spool carrier will bereliably prevented from rotating with the rotor during operation, and onthe other, that the stresses occurring in case of malfunction will beheld within such limits that they can be accepted by the machine withoutdamage or even destruction of individual parts.

This task is solved by locating the center of gravity of the spoolcarrier with the inserted spool, essentially within the axis of therotor, and by coupling to the spool carrier an unbalanced mass whichwill prevent its rotation, consisting of a counterweight which canindependently rotate about the axis of the rotor, and which may, onexceeding a predetermined value of the torque in the clutch to the spoolcarrier, become uncoupled from the latter.

By the invention, the centrifugal forces that occur, will be reduced tosuch an extent, that the stresses generated in case of malfunctioning bythe swing safety shutting-down the machine, are so reduced that nodanger exists for the machine or for the operator. If, for example, aspool carrier bearing should seize, the spool carrier may be acceleratedso high that it will rotate with the speed of the rotor, but as soon asthe predetermined value of the torque in the clutch between the spoolcarrier and the counterweight has been exceeded, this connection isbroken. By suitable setting of the value of the torque, it is simple toachieve that during normal operation the counterweight, acting asstabilizing unbalanced mass, will be coupled to the spool carrier withsufficient security, while the torque that will be transmitted to thecounterweight by the spool carrier when coming into rotation, may bekept so small that the maximum speed of the counterweight that may bereached until the machine comes to a stop, will be only a fraction ofthe rotor speed, wherein no dangerous stresses can occur. Rotating ofthe spool carrier with the rotor, the center of gravity of theformer--without the unbalanced mass coupled to it--lying as perinvention in the axis of the rotor, will not cause any additionaldangerous stresses.

By the characteristics of the claim 2, it is made possible to have thespool carrier of an essentially symmetrical design and to have thecenter of gravity, with a spool inserted, always lying in the axis ofthe rotor, independently from the spool in the spool carrier being fullor empty.

A perticularly exact setting of the value of the torque at which, as perinvention, the counterweight is released from the spool carrier, can beachieved by a torque clutch, for example by spring-loaded balls ordiscs. Since however, the machine will anyway come to a stop in case ofa malfunction, a shear bolt as per claim 4, which will become destroyedwhen the torque it is to transmit is exceeded, and which will thusrelease the counterweight, may be used as a particularly simple elementto connect the counterweight to the spool carrier. When checking, and,in case of need, re-setting the machine, a new shear bolt maysubsequently be inserted without any particular expenditure of time orof installing labor.

It is of particular advantage to support the counterweight as per claim5 on the trunnion ring of spool carrier bearing so that it can rotate,because in normal operation this bearing is stationary, and, afterreleasing of the counter weight, only relatively low speeds can bereached, so that this bearing will not be subjected to a high load.

In order to design the balanced mass of the counter weight as small aspossible, it is, as per claim 7, connected with the bearing by a leverthat is as long as possible.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is, in a schematic view, a part of the rotor of a high-speedstranding machine with two spools arranged in succession, and with theirspool carriers;

FIG. 2 is a section through FIG. 1 along the line II--II; and

FIG. 3 is a sectional drawing of the spool carrier bearing with thecounterweight connected.

DESCRIPTION OF PREFERRED EMBODIMENT

In FIG. 1, two spools are arranged in succession, supported so they canrotate each in the spool carriers 4, within a rotor 1 of a high-speedstranding machine which--depending upon the size of the machine--willrotate about the rotor axis 2 at speeds that may range from 1000 rpm to5000 rpm. To allow changing of the spools 3, windows 5 are provided inthe rotor wall. The spool carriers 4 are essentially symmetrical spoolsupports, the axis of rotation of which coincides with the rotor axis 2.The axes of the spools 3 intersect, as can also be seen from FIG. 2. Therotor axis 2. This makes possible that the center of gravity of thespool carrier 4 when carrying a spool 3, will be located exactly in therotor axis 2 so that any imbalance is avoided, independent from thespool 3 being full or whether more or less wire has already been reeledoff. If such a spool carrier 4 with spool 3 should be accelerated andeven rotate at the full rotor speed, the momentary load exerted upon thespool carrier bearings 6, 6' will not exceed their carrying capacity.The bearing forces will be transmitted via the rotor 1 onto the rotorbearing which is not shown. The stress upon the rotor 1 is so small thatthe stress upon the remaining sectional area of the rotor wall betweenthe rotor windows 5, will be only slightly above the normal stress.

A counterweight 6 is arranged on the spool carrier bearing 6. It isconnected with the spool carrier 4 and thus forms an unbalanced masshindering the spool carrier 4 from rotating together with the rotor 1.Should the spool carrier 4 be accelerated by a broken wire, a defect inone of the spool carrier bearings 6, 6' or by something of a similarnature, so that it begins to co-rotate, the connection between thecounterweight 7 and the spool carrier 4 will be broken upon exceeding ofa predetermined value of the torque in the clutch between these twoparts.

In FIG. 3, the spool carrier bearing 6 on which the counterweight 7 isarranged, is shown in detail in a particularly advantageous arrangementas per claim 6. The trunnion ring 8 has a collar 9 on its side oppositeto the spool not shown, and to the spool carrier 4 respectively, whichholds the former. This collar 9 encloses, at a small distance, thehollow trunnion 10 of the spool carrier bearing 6, which is arranged onthe rotor 1 and through which the wire 11 which is being unwound fromthe spool 3 is lead out. The outer jacket of the collar 9 forms theinner race of an antifriction bearing 12 in which the counterweight 7 isso supported that it can rotate. During normal operation, the bearing 12is however held stationary by the counterweight 7 being connected to thetrunnion ring 8 by a torque clutch 13 in such a manner that no rotationis possible. The torque clutch 13 in FIG. 3 consists of a minimum of oneball 14 which is pressed by the spring 15 into a bore 16 in the trunnionring 8. By an appropriate design of this spring loading, it is possibleto make a very exact setting of the torque value at which the ball 14will slide out of the bore 16, thus releasing the counterweight 7, sothat it may rotate freely in the bearing 12 relative to the spoolcarrier 4, and will not participate in a further occurring accelerationof the spool carrier 4.

Instead of the spring-loaded torque clutch 13 shown in FIG. 3, theconnection between the counterweight 7 and the trunnion ring 8 may alsobe made by means of a shear bolt, the thickness of which must be sodesigned that it will break at the predetermined value of the torque.Since the malfunctions against whose effects the design of the quickstranding machine as per invention is to protect, do not occur veryfrequently, a new shear bolt may simply be inserted in such a caseduring the shut-down of the machine which will then occur anyway.

In order to hold as low as possible the load stress of the spool carrierbearing 6 by the counterweight 7 arranged on it, the lever arm by whichthe unbalanced mass of the counterweight 7 is connected to thecounterweight bearing 12 should, as per claim 7, be as long as possible,and thus, a relatively small mass will attain an imbalance that willprevent a co-rotation of the spool carrier 4 with the necessary degreeof security. The possible length of the lever is limited by the designof the machine, that means by the free space in the rotor 1 that isavailable for the counterweight 7.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofconstructions differing from the types described above.

While the invention has been illustrated and described as embodied in aquick-stranding machine, it is not intended to be limited to the detailsshown, since various modifications and structural changes may be madewithout departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this invention.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims:
 1. A high-speed stranding machine,comprising a hollow rotor rotatable about an axis of rotation; at leastone spool carrier arranged in said rotor independently of the rotationof said rotor; an unbalanced mass arranged to prevent rotation of saidspool carrier together with the rotation of said rotor and formed as acounterweight, said spool carrier with a spool carried thereby having acenter of gravity substantially coinciding with said axis of rotation ofsaid rotor; and means for connecting said counterweight with said spoolcarrier so that said counterweight can independently rotate about saidaxis of rotation of said rotor, and can be disconnected from said spoolcarrier upon exceeding a predetermined torque value in said connectingmeans.
 2. A high-speed stranding machine as defined in claim 1, whereinsaid connecting means includes a clutch connection.
 3. A high-speedstranding machine as defined in claim 1, wherein said spool carrier isarranged so that a spool carried thereby has an axis which intersectssaid axis of rotation of said rotor.
 4. A high-speed stranding machineas defined in claim 1, wherein said connecting means is formed as anadjustable torque clutch connecting said counterweight with said spoolcarrier.
 5. A high-speed stranding machine as defined in claim 1,wherein said connecting means is formed as a shear bolt connecting saidcounterweight with said spool carrier.
 6. A high-speed stranding machineas defined in claim 1; and further comprising a bearing which supportssaid spool carrier in said rotor and has a trunnion ring, and means forrotatably supporting said counterweight in said rotor and including saidtrunnion ring arranged to rotatably support said counterweight.
 7. Ahigh-speed stranding machine as defined in claim 6, wherein saidtrunnion ring has a side facing away from said spool carrier and isprovided with a collar at said side, said counterweight supporting meansincluding a further bearing with an inner race formed by said collar. 8.A high-speed stranding machine as defined in claim 1; and furthercomprising means for rotatably supporting said counterweight in saidrotor, said counterweight supporting means including a lever which isconnected with said counterweight for joint rotation therewith andelongated in direction from said axis of rotation of said rotor towardsaid counterweight.
 9. A high-speed stranding machine as defined inclaim 8, wherein said rotor has an inner hollow of a predeterminedradial dimension, said lever of said counterweight supporting meanshaving a length which substantially corresponds to said radialdimension.